Why the World Health Organization Just Backed a Mosquito

April 29, 2016

The World Health Organization (WHO) steps in to fight the worst global health crises. From the HIV/AIDS epidemic1 to the deadly Ebola virus2, the organization plays an integral role in recommending appropriate courses of action and coordinating global response.

With the emergence of the mosquito-borne Zika virus being linked to microcephaly, a rare neurological condition in which babies are born with small heads and brain damage, and Guillain-Barré syndrome, a condition that causes temporary paralysis in adults, the agency is stepping in again.

Two months after declaring Zika a public health emergency of international concern3, the microcephaly speculation was confirmed. According to a WHO news release, there is “strong scientific consensus” that the virus puts developing fetuses at higher risk of the condition.4

Since Zika spreads to people primarily through the bite of an infected Aedes aegypti mosquito, in March, the agency recommended that officials in Zika-prone areas consider carefully planned pilot programs involving Oxitec OX513A mosquitoes. These mosquitoes which live less than a week have been genetically engineered so their offspring die before they reach adulthood, and are currently available to defend against the spread of the Zika virus and other diseases carried by the Aedes aegypti species, including dengue fever, chikungunya, and yellow fever.5

Due to their self-limiting nature, Oxitec OX513A mosquitoes do not persist in the environment, unlike other alternatives currently being considered, including Wolbachia, chemical insecticides, and radiation-based sterile insect technique. These other mosquito control techniques also introduce random genetic changes in the mosquito genome, yet Oxitec mosquitoes come under more intense scrutiny by both regulators and stakeholders as they fall into the narrow definitions of genetic engineering.

The Outbreak

According to the Centers for Disease Control and Prevention (CDC), prior to 2015, outbreaks occurred in parts of Africa, Southeast Asia, and the Pacific Islands. Currently, the Zika virus is in more than 30 countries and territories worldwide, including the Americas, Pacific Islands and Africa, and continued rates of global travel will likely only accelerate the spread of the virus.

Moreover, although Aedes aegypti mosquitoes are the primary method of Zika transmission, sexual transmission is also possible.

While there are no confirmed deaths from the Zika virus, the WHO estimates that as many as 4 million people could be infected by the end of the year.6

The Bottom Line

Since there is no approved treatment or vaccine available7, concern is rising around Aedes aegypti and the viruses they carry. In response, the WHO is looking at the science being used to understand — and ultimately eradicate — the problem.

“While we are fighting Zika, we’re also fighting against any other viruses that a mosquito can potentially transmit,” says Oxitec’s Field Trial Supervisor Cecilia Kosmann. “Our concern is not only with Zika, it’s with the mosquitoes that transmit disease.”

1 http://www.who.int/mediacentre/factsheets/fs360/en/

2 http://apps.who.int/ebola/our-work/achievements

3 http://www.who.int/mediacentre/news/statements/2016/emergency-committee-zika-microcephaly/en/

4 http://www.who.int/features/qa/zika/en/

5 http://www.who.int/neglected_diseases/news/mosquito_vector_control_response/en/

6 https://www.washingtonpost.com/news/to-your-health/wp/2016/02/01/zika-virus-who-declares-global-public-health-emergency-given-rapid-spread-in-americas/

7 http://www.who.int/mediacentre/factsheets/zika/en/